The present disclosure relates to inkjet recording devices.
Inkjet recording devices are compact and low in cost as compared to electrographic recording devices, need no fusing device to enable reduction in power consumption, and therefore, are widely used as printers, copiers, multifunction peripherals, etc. An inkjet recording device ejects ink droplets from a plurality of nozzles provided at its nozzle head to form an image on a recording medium such as paper.
Inks used in the inkjet recording device are divided into oil inks containing an organic solvent as a main solvent and water based inks containing water as a main solvent. In response to a demand for environmental awareness, development of water based inks containing no environmentally harmful organic solvent has been promoted.
In the case using a water based ink, water may penetrate through the print surface of paper to cause fiber of the paper to swell. As a result, expansion of the print surface may become larger than that of the non-print surface of the paper. This may tend to produce a difference in extension between the print surface and the non-print surface. In other words, a difference in stress may be liable to be produced between the print surface and the non-print surface. Due to the stress difference, a phenomenon of curling or cockling may be caused that the print surface curls into a convex shape.
A technique to reduce curling has been known that decurls and smooths down the paper in a direction reverse to the curling. A certain decurling mechanism includes a hard roller and a soft roller in press contact with each other. The decurling mechanism can reduce curling in a manner that printed paper is allowed to pass between the rollers to be warped in the direction reverse to the curling direction.